气象因素对锡林河融雪径流影响的通径分析

Path analysis about the impacts of atmosphere factors on snow-melt runoff of Xilin River

以锡林河流域为研究对象,针对锡林浩特、阿巴嘎旗、林西和克什克腾旗4个国家气象站,1960—2010年的逐日气象数据和锡林浩特水文站1960—2010年的实测径流数据,利用相关分析、偏相关分析和通径分析等方法,在年时间尺度和季时间尺度上研究降水、气温、最高气温、最低气温、日照时数、潜在蒸散发和有效积温等气象因素与径流的相关性、偏相关性,并通过通径分析,确定其对径流影响的直接作用和间接作用。结果表明:在年时间尺度上,日照时数、年均气温、最低气温和最高气温与径流量的相关性不显著,其对径流的直接影响和通过其他因素对径流的间接影响也较小,不是影响径流变化的主要气象驱动因素;降水、蒸发和有效积温与径流的相关性较高,这3种因素对径流的直接影响也较大,是影响流域径流的主要气象因素。在季时间尺度上,对锡林河流域径流变化影响较大的前3种因素依然是降水、蒸发和有效积温;但不同季节、不同气象因子对流域径流影响的贡献不同,春季起主要控制作用的是有效积温,夏季和秋季起主要控制作用的是降水。

[Background] Surface runoff of cold and arid regions is particularly sensitive to climate change,climate factors such as precipitation,potential evaporation,temperature of the slight change,can cause the change of surface runoff system. At present,the impacts of climate change on runoff,mainly were focused on single statistical analysis on the impact of meteorological factors on runoff,and ignoring the mutual influences among the impact factors. In fact,the complicated relationship between meteorological factors is multivariate. [Methods] Taking Xilin River basin as research target,the relationship between runoff and varied factors of precipitation,average temperature,highest temperature,lowest temperature,sunshine duration,potential evaporation and effective accumulated temperature were studied on yearly time-scale and seasonally time-scale by the method of correlation,partial correlation and path analysis,and their direct and indirect impacts on the runoff were determined by path analysis. Thedata were obtained from 4 national weather stations in 1960—2010,one weather station is Xilinhot station in the area,and other three are Abaga,Linxi and Keshiketeng stations near the area. The runoff data were from Xilinhot hydrometric station measured in 1960—2010. [Results]There were two obvious flood seasons of runoff process in Xilin River,they were April spring flood and the summer flood in July. The correlations between runoff and factors of sunshine duration,annual average temperature,minimum temperature and maximum temperature in yearly time-scale were insignificant. Both the direct effects and the indirect effects through other factors on the runoff were also little,thus they were not the main meteorological driving factors affecting the runoff. The correlation between runoff and precipitation,potential evaporation,effective accumulated temperature was highly significant,and the direct effects of them on runoff was high,therefore they were the main factors affecting on the runoff in yearly time-scale.On the seasonally time-scale,the top 3 factors impacting runoff were also potential evaporation,rainfall and effective accumulated temperature. Different weather factors contributed differently to the runoff of Xilin River in different seasons; the main control factor was effective accumulated temperature in spring,while in summer and autumn the main atmosphere control factor was precipitation. Due to the influence of seasonal frozen soil,the correlation coefficient and direct path coefficient between runoff and accumulated temperature was significantly higher than the those between runoff and temperature,especially in the spring,the direct path coefficient between runoff and accumulated temperature even was higher than that between runoff and precipitation. [Conclusions] The direct correlation between runoff and atmospheric variables can be determined by path analysis in the study of relative importance of each climatic factor,thereby determining the impacts of those factors on runoff change and providing a reliable basis for decision-making.